Conventional dispensing systems for liquids generally comprise a pressurized supply and a dispensing valve which is open for a predetermined period of time such that a predetermined quantity of liquid is delivered therethrough. While systems of this type are suitable for many purposes, they are not entirely suitable for viscous substances such as syrups, custards, jellies, or materials which contain semi-solid elements. The quantity of substance which may flow in a given time may vary, and shut off of the dispensing valve may be difficult.
In my prior U.S. Pat. No. 3,734,352 a dispensing system is disclosed and claimed including a dispensing cylinder and a pilot operated spool valve for controlling the dispensing cylinder. This system is efficacious in solving the problems associated with viscous substances in that positive displacement of a definite quantity of material is provided together with quick severing of semi-solid elements in the dispensed material through action of the spool valve. The present invention comprises an additional improvement in this type of apparatus wherein the control and dispensing elements are provided in a unitary block adapted for multiple utilization with other similar units. The apparatus is simplified but requires a single source of air under pressure for operation, while also providing for external adjustment of the quantity of material dispensed.